Problem: Emily went to soccer practice $6$ times last month. Each practice is $90$ minutes long. How long did Emily spend at soccer practice last month?
Answer: ${90}$ minutes is the same as ${9\text{ groups of ten}}$. Emily went to $6$ practices. Total number of minutes: $\begin{aligned}&\phantom{=}6\times{9\text{ groups of ten}}\\\\ &=C{54\text{ groups of ten}}\\\\ &=C{540}\end{aligned}$ Emily spent $C{540}$ minutes at soccer practice last month.